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THE UNIVERSITY OF DA NANG UNIVERSITY OF SCIENCE AND TECHNOLOGY BUI VAN TAN IMPROVING ECONOMIC, TECHNICAL CHARACTERISTICS AND REDUCING EXHAUST EMISSIONS OF MOTORCYCLE ENGINE FUELED WITH LPG AND ETHANOL Major : Mechanical Engineering Code : 9520116 SUMMARY OF TECHNICAL DOCTORAL THESIS DA NANG - 2021 -1- Work completed at: UNIVERSITY OF SCIENCE AND TECHNOLOGY Science Instructor : Prof D.Sc BUI VAN GA Assoc Prof Dr Tran Thanh Hai Tung Reviewer : ………………………………………………… Reviewer : ………………………………………………… This thesis will be defended in front of panel of judges from University of science and technology-University of Da Nang, At: …… o’clock …… of ……… , 2021 This thesis can be found at: - National Library of Vietnam - Learning Resources and Communication Center, University of science and technology- The University of Da Nang -2- INTRODUCTION Essential Unlike other developed countries, motorcycle is main means of individual transport in our country with the average density of people on motorcycle Environmental pollution has become worse and worse in big cities caused by motorcycle’s emissions The study on the engine fueled with ethanol or biogasoline has been conducted by several scientists; however, the study on motorcycles’ engine fueled with LPGethanol blends has been rare Therefore, the thesis “Improving economic, technical characteristics and reducing exhaust emission on engine fueled with LPG and ethanol” means a great contribution and essential Study Objectives An optimal advantage of the benefits of LPG and ethanol as alternative fuels on motorcycle aims at saving our fossil fuel, reducing pollutant emissions and CO2 Objects and scope of the study Our object is the J52C engine of motorcycle Honda RSX 110cc, equipped with cylinder, stroke, electroniccontrol fuel injection Scope of the study: The study on intake and combustion process, economic, technical characteristics and exhaust emission on engine fueled with hybrid LPG and ethanol fuel Study methods The thesis uses simulation and experiment as the study method Based on this basic study result, we are orientated towards development of fuel supply technology and organization of combustion stroke of the motorcycle engine using LPG-ethanol hybrid fuel The thesis content layout Besides introduction and summary, the main content is presented -1- in chapters with the following layouts: Chapter 1: Overview of the research and application of LPGethanol fuel on the internal combustion engine Chapter 2: The research on combustion theory Chapter 3: The simulation of intake, combustion process and pollutant emissions on the motorcycle engine fueled with LPG-ethanol Chapter 4: Experimental study and assessment of stimulation results Scientific and practical significance of the research topic The application of LPG and ethanol as fuel will make complete use of their own advantages to improve the combustion process and enhance characteristics of the engine Due to the different states of LPG and ethanol in the environmental condition, their applications on motorcycle engine needs to be resolved related to fuel supply and organization of the combustion process This is a complex issue, until now the publication of scientific research results is still rare Thus, the thesis only carries scientific meaning but also highly practical reality just when there is a clear sign of crisis in fossil fuel, oil's depletion and severe climate change New points of the thesis Form a solid basis for development research in application of fuel at different states on motorcycle in particular and on motor vehicles in general Set up the mathematical simulation of the intake process of LPGethanol and combustion process on engine using air/liquid fuel in general Modify fuel injection system on motorcycles into multi-fuel liquid/gas injection system by adding chip control connecting ECU of the engine This system enables adjustment of the fuel ratio supplied -2- flexibly to the engine, which is suitable for the engine operating modes Draw the laws of impact from different factors in technical characteristics and levels of pollutant emissions of motorcycle engine orientated to designing, manufacturing fuel supply system as well as LPG-ethanol fueling engine control system Chapter OVERVIEW OF THE RESEARCH STATUS OF ETHANOLLPG APPLICATION ON THE INTERNAL COMBUSTION ENGINE 1.1 Clean fuel Energy is a matter of survival for all mankind, while humans are exploiting all sources of fossil energy to the fullest extent (oil, natural gas, coal ), whereas with such limited reserves and increasing consumption speed, our world is facing the gradual depletion of this kind of source 1.2 Situation of biofuels usage 1.2.1 Situation of biofuels usage in the world Brazil is the world leading country in this field, the largest ethanol fuel producer and consumer with 14,7 million gallons After 2017, The US produces 132.000 million liters of biofuels annually to reduce 20% gasoline consumption Thailand had the capacity of 192,8 million liters of ethanol fuel in 2007 China is the third largest producer and consumer of ethanol fuel beside Brazil and the US China was set to triple its ethanol production capacity by 2020, estimated annual production capacity of 15 million tons needed (01 ton ethanol fuel equivalent to 1,267.93 liter) 1.2.2 Situation of biofuels usage in Vietnam According to Decision No 53/2012/QD-TTg dated November 22, 2021 by the Prime Minister, the ratios for blending biofuels with the -3- conventional fuels Following the world trend, Vietnamese scientists are interested in researching biofuels over the decade, yielding some fruits accompanied by the publication of possible application 1.3 Situation of research on the usage of LPG on the internal combustion engine 1.3.1 Basic characteristics of LPG fuel Boiling temperature of LPG is lower than room temperature, thus LPG evaporates quickly at normal temperature and pressure and is stored in the steel pressure vessel It is normally filled up to 85% volume of the vessel allowing thermal expansion of containing liquids The ratio between vaporized gas and liquefied gas change depending on composition, pressure and temperature, is normally around 250:1 The pressure making LPG a liquid is called steam pressure that changes depending on composition and temperature, respectively 1.3.2 Research the use of LPG on the automobile engine There have been several researches in application of LPG on the internal combustion engine in our country Fig 1.4: The mini “Greenbus” runs on LPG Fig 1.3: Set up a carburetor using LPG Since 2005, Ho Tan Quyen from Uiversity of Da Nang who succeeded in manufacturing a system supplying LPG for Daihatsu cars on the basis of the carburetor and he later applied research on twowheeled motorcycles 1.3.3 Research the use of LPG on motorcycle engine -4- Many researches on application of LPG on motorcycles conducted by a group of researchers from Polytechnic University, University of Da Nang, and the basic issue needed solution is to design a compact LPG/gasoline dual fuel system that is easily installed on motorcycles without altering their own patterns or compositions Fig 1.5: The 110cc-motorcycle Fig 1.6: The model WAVE 110cc engine after being installed with after successfully installed with a a LPG/gasoline dual fuel LPG/gasoline dual fuel system carburetor 1.4 Situation of research on application of LPG on the internal combustion engine The application of ethanol as a fuel for internal combustion engine through direct injection of ethanol into the combustion chamber or separate injection of gasoline/ethanol on the intake manifold, by that way it is only able to bring a solution to alternative fuels but also take advantages of benefits given by ethanol fuel including engine performance improvement, reduction of emissions of CO, HC and CO2 respectively and limitation of increased NOx compared to gasolineethanol mixture injection on the conventional intake manifold 1.5 Situation of research on application of LPG-ethanol blend on the internal combustion engine There have been many researches concerning the application of ethanol-LPG mixture on SI engine aimed at reducing exhaust emission but the results found mainly focused on automobile engines and -5- operating conditions Concerning motorcycle engines with different specifications such as small cylinder capacity, high speed, air cooled They have yet to catch attention for research 1.6 Conclusion - Use LPG and ethanol combined as fuels on the engine enables us to take advantages of benefits given by each kind to improve quality of the combustion process and reduce pollutant emissions Due to different states of LPG and ethanol under same environmental conditions, the system supplies fuel more in a complex way compared to that of gasoline-ethanol mixture - The combination of LPG and ethanol on motorcycles is an essential solution and feasibility to reducing dependence on fossil fuels and environmental pollution There have been many researches on application of LPG, gasoline-ethanol on motorcycle engine in particular and motor vehicles in general, whereas there has been rarely the publication of research on application of LPG-ethanol on motorcycles CHAPTER 2: THEORETICAL RESEARCH OF THE COMBUSTION PROCESS 2.1 Equation of turbulent flow Turbulence model is often represented by the turbulent kinetic energy k and rate of dissipation of turbulent energy obtained through the following transport equations: ( k ) ( ku ) i x t xi j ui t xi x j t k k P P Y S x k b M K j t 2 C1 Pk C3Pb C2 S x j k k (2.6) (2.7) 2.2 Theory of gaseous combustion process In mathematic simulation, thermodynamic problems are simplified -6- into a single parameter - mixture composition f f is a conserved quantity in this conservation equation without a source 2.2.1 Combustion theory of non-premixed mixture 2.2.1.1 Theory of the mixture composition Mixture composition can be written in an atomic mass as follow: f Z i Z i, ox (2.8) Z i, fuel Z i, ox 2.2.1.2 A turbulence-chemistry interaction model a Description of probability density functions Probability density function is denoted as p(f), presented by the following formula: p( f )f lim i T T i (2.17) b Derivative of mean quantity values from instantaneous mixture component Probability density function p(f) describes variations of f in the turbulent flow used for calculating instantaneous values of f-dependent parameters i p(f )i (f )df (2.18) 2.2.1.3 Expansion of combustion modeling of premixed mixture on non-adiabatic cases The indication i in the non-adiabatic system really requires numerical solution of transport equation to average enthalpy: k ( H ).( v H ). t H Sh cp t (2.25) 2.2.2 Combustion theory of premixed mixture 2.2.2.1 Flame spread Flame spread modeling is shown by solving the transport -7- equation for instantaneous reaction rate, denoted c ( c).( v c). t c Sc t Sc t (2.26) 2.2.2.2 The turbulent flame speed In Fluent, the turbulent flame speed is computed using a model for wrinkled and thickness flame fronts: U t A( u')3/ U l1/ 2 1/ lt1/ (2.29) 1/ U t Au' t c 2.2.2.3 The laminar flow speed The laminar flow speed (Ul in the equation 2.32) can be a constant or a user-defined equation U l U l ,ref Tu Tu ,ref pu pu ,ref (2.32) 2.2.2.4 Combustion models of premixed mixture in Fluent Calculate the source Sc, based on the given theory: Sc AG.u I / U l ( lp ) 1/ ( lp ) 1/ 1/ t l c (2.35) 1/ Sc AGu I t c (lp ) c (2.36) 2.2.2.5 Calculate the adiabatic temperature a Calculate the adiabatic temperature For the adiabatic combustion model of premixed mixture, in the adiabatic condition Tad: T = (1-c)Tu + cTad (2.37) b Calculate non-adiabatic temperature The energy equation is written according to increasing enthalpy, h, for complete fuel mixture as mentioned below: -8- 3.3.3 The process of mixture formation from LPG-ethanol spraying t (ms) Ethanol n=5000 rpm (%V) LPG (%V) 140 n=3000 rpm 140 Fig 3.6: Evolution of particle density and distribution of Ethanol, LPG in cylinder showed when the engine operates at 5000 rpm and 3000 rpm respectively, BG0, Tinit=310K, k=1, =1 thuc Fig 3.6 shows that ethanol evaporates quickly after spraying which definitely creates ethanol-rich area along the intake manifold opposite the nozzle At the end of intake stroke, the cylinder has been divided into two distinct areas separated by a rich streak LPG fuel 300 Ethanol LPG (%V) (%V) 330 360 Fig 3.8: Changes in particle density and distribution of Ethanol, LPG in cylinder showed when the engine operates at 7000 rpm, respectively, BG0, Tinit=310K, k=1, =1 During compression stroke, relatively LPG-rich fuel area gathers near the ignition candle while ethanol-rich fuel area gathers quite far away from the ignition candle (fig 3.8) In this case, distribution of fuel concentration is remarkably beneficial for the combustion process Ethanol has a high octane number, thus its distance away from the ignition candle prevents engine knocking due to great increase of pressure and mixture temperature Octane stratification in the mixture is a great advantage to forced ignition engines fueled with ethanol -11- 60 0.05 50 40 0.04 30 0.03 20 0.02 10 0.01 0 60 120 180 (CA) 240 0.06 dpm (g/m3) Ev (mg/s) 40 0.04 30 0.03 20 0.02 10 0.01 300 0.05 Evaporation Rate (mg/s) dpm (g/m ) Ev (mg/s) 50 0.06 Liquid Particle Density (g/m3) Evaporation Rate (mg/s) Liquid Particle Density (g/m3) 60 0 60 120 180 (CA) 240 300 145 141 3.9 137 3.8 133 3.7 129 3.6 125 3.5 0.9 0.95 1.05 1.1 Pe (kW) Wi (J/ct) (a) (b) Fig 3.12: Variation of liquid fuel particle density and evaporation rate in ethanol E15L (a) and E30L(b) with crankshaft rotation angle (n=5000 rpm, Tinit=315K) Fig 3.12 for E15L (a), the evaporation process ends around =180CA, it means that by the end of intake process, most of ethanol fuel particles evaporates completely Unlike for E30L (b), evaporation process of liquid fuel particles lasts till the end of the compression process Therefore it is essential to find a solution to supporting ethanol evaporation using fuel with more 30% ethanol content on motorcycle engine 3.4 Simulation of combustion process 3.4.1 The coefficient of equivalence effect Fig 3.26: Effect of the coefficient of equivalence on the cycle indicator Wi and useful power output Pe (E30L, n=5000 rpm, s=20CA) The result shows that the cycle indicator reaches the maximum value corresponding to combustion mixture =1,08 (fig 3.26) With such a coefficient of equivalence, the cycle indicator Wi increases 3% -12- compared to the case =1 3.4.2 Effects of ignition advance angle o CA) s((TK) 50 50 s 30 s (TK) 40 10 15 20 25 30 35 30 p (bar) 40 p (bar) s(oCA) 10 15 20 25 30 35 20 20 10 10 0 120 150 180 210 (TK) 240 270 20 40 (oCA) 60 V (cm3) 80 100 120 (a) (b) Fig 3.28: Effects of ignition advance angle on pressure variation in the cylinder by the crankshaft rotation angle (a) and by working volume (b) (E30L, n=5000 rpm, =1) The cycle indicator reaches the maximum value when chart area reaches the maximum value, corresponding to optimal ignition advance angle with the given operating mode of the engine 160 148 5.2 136 4.4 124 3.6 112 2.8 100 2000 3000 4000 5000 n (v/ph) 6000 Pe (kW) Wi (J/ct) 3.4.3 Effects of the engine speed 7000 Fig 3.33: Effects of the engine speed on the cycle indicator Wi and useful power output Pe (E30L, =1, optimal ignition advance angle) n (rpm) The cycle indicator decreases 156 J/cyc down to 117 J/cyc when the engine speed increases 2000 rpm up to 7000 rpm (fig 3.33) in the case of optimal ignition advance angle 3.4.4 Effects of ethanol content -13- E0L E0 E100 E100L p (bar) 30 50 40 20 10 p (bar) 40 10 HRR (J/CA) 50 E0L E0 E15 E15L E30 E30L E45 E45L E70 E70L E100 E100L 30 20 10 0 120 150 180 210 240 270 300 330 360 (CA) 20 (a) 40 60 80 V (cm3) 100 120 b) Fig 3.35: Effects of ethanol content on pressure variation and heat release rate (a) and on pressure variation by working volume (b) (=1, n=4000 rpm, s=20CA) Result of simulation (fig 3.35a) shows maximum pressure obtained by ethanol (E100L) engine higher than that of LPG (E0L) engine With increase in ethanol content, the pressure during compression stroke decreases while the pressure during combustion stroke increases leading to increase in chart area, thus increase in cycle indicator (fig 3.35b) Result of calculation shows that the cycle indicator of the engine reaches 130, 134, 136, 150 and 152 J/cyc respectively with E0, E15, E30, E45, E70, E100 3.5 Simulation of pollutant emission 3.5.1 Effects of coefficient of equivalence on variation of HC, CO, NOx CO, HC, NOx (ppm), T (K) 5000 4000 NOx CO HC T Fig 3.39: Summarize the effect of the equivalence coefficient 3000 on variation of HC, CO and NOx 2000 concentration and combustion 1000 temperature 0.9 0.95 1.05 1.1 of the engine (E30L, n=5000 rpm, s=30CA) In this operating condition (fig 3.39), temperature of the gas mixture reaches the maximum value corresponding to within 1,03 ÷1,08 NOx concentration remains stable when is more than 1,03 While CO, HC -14- concentrations increase sharply as >1 due to incomplete combustion process 3.5.2 Effects of ignition advance angle on variation of HC, CO and NOx concentrations As we can see the slight change of the emission temperature (fig 3.43) when ignition advance angle increases 10CA up to 35CA and NOx concentration increases 50%, CO and HC concentrations decrease 50% averagely Fig 3.43: Summarize the effects of ignition advance 4000 CO, HC, NOx (ppm), T (K) NOx CO HC T 3000 angle s on variation of HC, 2000 CO and NOx concentration and combustion temperature 1000 T (E15L, n=5000 rpm,=1) 10 15 20 25 s o(TK) 30 35 ( CA) 3.5.3 Effects of engine speed on variation of HC, CO and NO x concentrations Fig 3.46: Summarize effects of the engine speed on variation of NOx, CO, HC concentrations and combustion temperature T 6000 CO, HC, NOx (ppm), T (K) 5000 4000 3000 NOx CO HC T 2000 (E30L, ϕ=1, φs=20CA) 1000 2000 3000 4000 5000 n (v/ph) 6000 7000 n (rpm) In contrast to CO emission, at the given operating condition and fueling mode, NOx concentration decreases as the engine speed increases (fig 3.46) As the engine speed increases, both combustion temperature and time decrease resulting in decrease in NOx concentration 3.5.4 Effects of ethanol content on variation of HC, CO and NOx concentrations -15- 2500 E0L E0 2000 E0 E0L E30 E30L E70 E70L E15L E15 E30L E30 T (K) HC (%V) E45 E45L 1500 E70 E70L E100 E100L 1000 E15 E15L E45 E45L E100 E100L 0.08 0.04 500 330 345 360 0 60 120 180 (TK) (oCA) 240 300 150 360 180 210 240 270 (CA) (a) 300 330 360 (b) 1500 1.5 E0L E0 E15L E15 1.25 1200 E30 E30L E45 E45L 900 E70 E70L 0.75 E100 E100L 0.5 NOx (ppm) CO (%V) 600 150 180 210 240 270 300 330 E15L E15 E45L E45 E100 E100L E0L E0 E30 E30L E70 E70L 300 0.25 360 150 (CA) 180 210 240 270 (CA) 300 330 360 (c) (d) Fig 3.47: Effects of ethanol content on variation of combustion temperature (a) and NOx (b), CO (c) and NOx concentrations (d) in the engine exhaust (n=5000 rpm, BG45, ϕ=1, φs=20CA) Due to high latent heat of evaporation of ethanol, as ethanol content increases, the intake air temperature decreases leading to decreased combustion temperature and mixture temperature shown on expansion line (fig 3.47a) Decreased combustion temperature leads to decreased NOx concentration according to the ethanol content Fig 3.47b shows NOx content in the exhaust fueled with LPG produces almost twice NOx content in the exhaust fueled with ethanol Because of increased flame speed, heat release rate and combustion process are likely improved with the presence of oxygen in ethanol fuel, and as ethanol content increases, it offers a complete combustion process, which leads to decreased CO and HC concentrations in the exhaust (fig 3.47 and fig 3.47d) It can be found in fig 3.35 and fig 3.47 that E30L fueling engine offers increased cycle indicator of 4.5%, reduced emission of NOx, CO and HC down to 13%, 20% and -16- 17% respectively compared to those of a complete LPG fueling engine 3.6 Conclusion - As spraying LPG-ethanol mixture into the intake manifold until the end of compression stroke, relatively LPG-rich areas gather near the ignition candle while ethanol-rich areas keep a distance from the ignition candle Due to such a distribution of fuel concentration, it is able to prevent the engine knocking - The soot concentration increases as there is an increase in ethanol content mixed with LPG Addition of ethanol to LPG will reduce levels of pollutant emissions - At fixed ignition advance angle, the engine speed increases leading to an increase in CO concentration, a decrease in NOx concentration At given engine speed, increasing ignition advance angle will decrease CO emissions, but increase NOx concentration instead CHAPTER 4: EXPERIMENTAL STUDY AND ASSESSMENT OF SIMULATION RESULTS 4.1 Objectives and limitations of experimental research - Manufacture engines’ load brakes, measure the torque and analyze engine emissions in some operating modes - Improve the LPG-ethanol supply system on motorcycles 4.2 Research equipment 4.2.1 Manufacture of load brake for motorcycle engine Fig 4.4: Structure diagram of load brake on a motorcycle engine Engine test, Drive shaft, Loadcell, Shelf, Electric brake, Cooling fan The engine load brake is innovated from a generator producing counter torque A force transducer (load cell), -17- engine speed sensor, throttle control (servo motor), the control circuit are all connected to the computer by a microcontroller board Arduino Uno R3 All sets of equipment of the motorcycle engine test system shown on fig 4.4 4.3 Switch from gasoline fueling motorcycles to LPG-ethanol fueling motorcycles Fig 4.8: Diagram of ethanol1 ECU Ethanol/LPG ratio Điều chỉnh adjustment Tỉ lệ nhiên liệu LPG multi-fuel supply system C on motorcycle engine C Butterfly valve position A B Arduino Microcontroller Auduino sensor, Intake air pressure sensor, Fuel pressure Pressure Ổnstabiliser áp B sensor, Speed sensor, Lọc Filter Detonation sensor, Ethanol Cylinder temperature sensor, Xăng/Ethanol Pump Bơm Oxygen sensor, A Control signal for ethanol injector, B Control signal for LPG injector, C Control signal for ignition Diagram of LPG-ethanol injection system for motorcycle engine shown on fig 4.8 The system consists of nozzles installed on the back of the throttle: liquid fuel injector nozzle for spraying ethanol, gas fuel injector one for spraying LPG LPG injector nozzle is installed next to ethanol injector one (reuse of fuel nozzle) An Arduino microcontroller added to ECU is used to control those nozzles The microcontroller receives the control signal of gasoline injector nozzle from ECU, then is divided into pulses of control signal with each pulse width determined by the ethanol/LPG ratio needed This method allows flexible adjustment of fuel ratio and modification of fuel system into compact and simple one 4.5 Motorcycle test using LPG-ethanol mixture based on the engine load brake -18- Fig 4.13: Diagram of experimental layout The engine Honda RSX fueled with Ethanol-LPG; + 11 Electric brake; Loadcell; Encoder; + 14 12 Resistance; Accu; 13 Load controller; 15 16 Microcontroller Arduino, Computer; 10 ECU RSX engine; 11 LPG injector; 12 Ethanol injector; 13 Ethanol tank; 14 LPG tank; 15, 16 Electric scale Fig 4.13 introduces diagram of experimental layout and system consisting of LPG-ethanol engine test connected to the load brake In this experiment, the engine speed is valued at: 2000, 2500, 3000, 3500, 4000, 4500 and 5000 rpm To ensure safety of the measurement system, the engine speed is limited at 5000 rpm The adjustment of the injection rate of ethanol and LPG by ExL=10% and ExL=40% accordingly 4.6 Assess experimental results and compare simulation results 4.6.1 Compare effects of the engine speed on characteristics of the engine given by simulation and experiment Simulation Experiment n=2000 rpm Simulation Experiment Simulation n=3000 rpm NOx (ppm) Experiment n=4000 rpm CO (ppm) HC (ppm) Simulation Experiment n=5000 rpm Pe (W) Fig 4.21: Compare effects of the engine speed on power and pollutant emissions of the engine obtained by by simulation and experiment (E30L, =1, s optimal) -19- CO concentration obtained by experiment is 8% higher than that of simulation at 2000 rpm and 5% higher at 5000 rpm HC concentration obtained by experiment is averagely 15% higher than the one obtained by simulation value while NOx concentration obtained is averagely 12% smaller than the one obtained by simulation 4.2 Fig 4.22: Variation of output power Pe based on Ethanol Pe (kW) 4.1 3.9 content varies from E0L to E40L obtained by simulation and 3.8 3.7 experiment using ethanol-LPG ━: Simulation, : Experiment 3.6 10 20 30 E (%V) 40 50 As it is found that there is 10% difference between experimental and simulation results with ExL=10% and 5% difference with ExL=40% respectively 4.6.2 Compare effects of the engine speed on characteristics of the engine given by simulation and experiment 0.3 1600 1400 0.2 NOx (ppm) CO (%V) 0.25 0.15 0.1 1000 800 0.05 600 10 20 30 E (%V) 40 50 (a) 700 600 500 400 300 200 10 20 10 20 E (%V) 30 40 50 (b) 800 HC (ppm) 1200 30 E (% V) 40 50 ━: Simulation, : Experiment Fig 4.23: Compare variation of CO concentration (a) and NOx concentration(b) and HC concentration (c) based on ethanol content which varies from E0L to E40L (=1, n=4000 rpm, s=20CA) -20- The difference is that value of CO, NOx concentration in the engine fueled with LPG mixed with 40% ethanol is lower than that of the engine fueled with LPG mixed with 10% ethanol E0L Simulation Pe (kW) E0L Experiment Coefficient Pe (kW) 4,2 CO (%) 0,27 HC (ppm) 700 NOx (ppm) 1500 Fig 4.24: Assess variation of output power Pe and levels of pollutant emissions of LPG engine(E0L) obtained by simulation and experiment (=1, n=4500 rpm, s=28CA) CO, HC concentration obtained by experiment is higher than the one obtained by simulation and NOx emissions obtained by experiment is lower than that obtained by simulation, the reason is that in reality combustion process is ideally incomplete beyond the simulation calculation E0L E40L Simulation Pe (kW) Coefficient Pe (kW) 4,5 CO (%) 0,15 HC (ppm) 410 NOx (ppm) 1200 Experiment Fig 4.25: Compare power and levels of pollutant emissions of the -21- engine operating on E40L fuel at 4500 rpm, =1, s=28CA HC concentration obtained by experiment is nearly as same as the one by simulation with E0L fuel It makes no difference between experiment and simulation on HC and NOx compared to E0L 4.7 Conclusion - It is certain that gasoline injection system can be modified into liquid/gas injection system by adding chip control connecting ECM of the engine - Variation of CO, HC concentrations in the engine exhaust with ethanol content obtained by experiment is higher than the one obtained by simulation but NOx concentration obtained by experiment is lower than the one obtained by simulation - The compatibility between simulation and experiment enables us to use simulation to predict the engine operating parameters using hybrid liquid/gas mixture CONCLUSION AND DEVELOPMENT Research results allow us to draw the following conclusions: Set up the mathematical simulation, model separate injection of ethanol and LPG fuel on the intake manifold, thus we can research in combustion process and pollutant emissions Simulation result: - As ethanol content is lower than 30%, liquid fuel particles evaporate completely during the intake stroke, and the cycle indicator Wi increases rapidly As ethanol content is higher than 30%, Wi increases slowly - For E30L fueling engine, the cycle indicator increases 4.5%, and emissions of NOx, CO and HC decreases down to 13%, 20% and 17% respectively compared to those of a complete LPG fueling engine Soot concentration in E30L fueling engine reaches only 50% of that in -22- ethanol E100L fueling engine - Optimal coefficient of equivalence ranges 1,03-1,08 with E30L fueling engine CO and HC concentrations in the exhaust increases quickly by coefficient of equivalence while NOx emissions remain almost constant as is higher than optimal value - When the engine operates on E15L fuel at 5000 rpm with increasing ignition advance angle from 10CA to 35CA, NOx concentration increases 50% while CO and HC concentrations decrease 50% averagely Gasoline injection engine can be modified into a separate injection engine using liquid/gas fuels by adding microcontroller circuit to split control pulse of original fuel injector into separate pulses with each pulse width proportional to the fuel composition needed Experimental results show: - CO, HC concentration in the engine exhaust obtained by experiment is higher than that obtained by simulation whereas the cycle indicator and NOx concentration obtained by experiment is lower than that obtained by simulation - For E30L fueling engine, power value obtained by experiment is about 10% lower than that obtained by mathematical simulation at 2000 rpm and 60% lower at 5000 rpm respectively CO concentration obtained by experiment is 8% higher than that by simulation value at 2000 rpm and 5% higher at 5000 rpm respectively HC concentration obtained by experiment is averagely 15% higher than that obtained by simulation while NOx concentration obtained by experiment is averagely 12% smaller than that obtained by simulation Results of development, application of the model: It is the first step to build the simulation (liquid/gas injector) -23- installed on Motorcycle Honda which is tested with the engine brake on the test road Under urban conditions, the engine J52C installed on Honda RSX 2014 fueled with addition of ethanol to LPG operating at about 4000 to 5000 rpm will be optimal for pollutant emissions DEVELOPMENT ORIENTATIONS This thesis can be developed to the following extents: - Complete LPG-ethanol hybrid fuel supply system on motorcycle engines orientated towards motorcycles operating on flexible fuel (Flexible Fuel Motorcycles); improve ECU of the motorcycle to allow for operating on flexible fuel - Measure technical characteristics and pollutant emissions of LPG-ethanol fueling motorcycles test to compare, assess efficiency in using LPG-ethanol compared to other conventional fuels in reality ANNOUNCED STUDIES Bui Van Ga, Bui Van Tan, Nguyen Van Dong: Effects of fuels, compression rate and ignition advance angle on combustion process of gasoline-ethanol mixture in Daewoo engine Journal of Science and Technology - The University of Da Nang, No [98], pp 22-26, 2016 Bui Van Ga, Tran Van Nam, Nguyen Van Dong, Bui Van Tan: Comparison of Performance and Pollution Emission of Engine Fueled with Gasoline Ethanol Blended Fuels and Biogas Journal of Science and Technology 112 (2016), pp 93-99 Bui Van Ga, Nguyen Van Dong, Bui Van Tan, Nguyen Quang Trung: Effects of composition H2 enriching Biogas on working characteristics and levels of pollutant emissions of the engine fueled with dual fuel biogas-diesel Proceedings Paper of the 20th National -24- Conference on Hydraulic Mechanics, Can Tho city, 27-29th July, 2017, City National University Publishing House HCM, 2018, pp 238-245 Tran Thanh Hai Hung, Bui Van Ga, Vo Anh Vu, Bui Van Tan: Eco friendly motorcycles Proceedings Paper of the 21st National Scientific Conference on Hydraulic Mechanics, QuiNhon, from 19th to 21st July, 2018, pp 894-906 Bui Van Ga, Le Minh Tien, Bui Van Tan, Vo Nhu Tung: Simulation of Engine Map on the engine fueled with hybrid biogas-gasoline Proceedings Paper of the 22nd National Scientific Conference on Hydraulic Mechanics, Hai Phong from 25th to 27st July, 2019, pp 250-259 Bui Van Ga, Duong Viet Dung, Le Minh Tien, Bui Van Tan: Compare simulation and experiment of characteristics on the motorcycle engine Honda RSX, 110cc with ethanol-LPG injection at the intake Proceedings Paper of the 23rd National Scientific Conference on Hydraulic Mechanics, Da Nang, on 7th November, 2020, pp 124-136 Bui Van Ga, Tran Thanh Hai Tung, Bui Thi Minh Tu, and Bui Van Tan: Effects of Ethanol Addition to LPG or to Gasoline on Emissions of Motorcycle Engines Operating Under Urban Conditions GMSARN International Journal 14 (4), 2020, 185-194 Bui Van Ga, Cao Xuan Tuan, Bui Van Hung, Nguyen Thi Thanh Xuan, and Bui Van Tan: Performance and Emissions of Motorcycle Engine Fueled with LPG-Ethanol by Port Injection CIGOS 2021, Emerging Technologies and Applications for Green Infrastructure Springer, Singapore, 2022 1673-1682 -25- ... motorcycles to LPG- ethanol fueling motorcycles Fig 4.8: Diagram of ethanol1 ECU Ethanol /LPG ratio Điều chỉnh adjustment Tỉ lệ nhiên liệu LPG multi-fuel supply system C on motorcycle engine C Butterfly... mixture formation from LPG- ethanol spraying t (ms) Ethanol n=5000 rpm (%V) LPG (%V) 140 n=3000 rpm 140 Fig 3.6: Evolution of particle density and distribution of Ethanol, LPG in cylinder showed... concentration increases as there is an increase in ethanol content mixed with LPG Addition of ethanol to LPG will reduce levels of pollutant emissions - At fixed ignition advance angle, the engine speed
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